EVALUATION CRITERIA FOR BAIT-TOXICANT EFFICACY AGAINST FIELD COLONIES OF SUBTERRANEAN TERMITES: A REVIEW

Abstract:
The applied objectives for bait-toxicant against subterranean termites are at minimum the suppression of foraging activity and ideally the elimination of the entire colony population. Subterranean termite colonies containing hundreds of thousands to millions of individuals may forage up to I50 m in soil. Effects of bait-toxicants against field colonies of subterranean termites are difficult to assess because of the cryptic nature of these insects. Use of toxicant-bait consumption to measure the effects of bait toxicant on foraging activity is misleading because it may only represent bait avoidance by termites. Measurement of the consumption of untreated baits placed in the vicinity of a target colony may be a more accurate reflection of the effects of bait-toxicants on overall foraging activity. Ideally, the interconnection between foraging populations found in toxicant-baits and untreated baits needs to be confirmed using dye markers or radioisotopes. The dye markers are also used to define foraging territories and population sizes of subterranean termites. Once the population of a target colony is characterized, the extent of colony suppression or elimination can be assessed.